The specific areas of proposed research are the following: 1) Replication of RNA Viruses:: Isolation and analysis of deletion and conditional lethal mutants of RNA tumor viruses and studies of animal virus associated protein kinase and phosphoprotein phosphatase. 2) Control of Gene Expression During Prokaryotic Developmental Processes: Studies of the regulatory mechanisms affecting the differentiation of Caulobacter crescentus. 3) Control Mechanisms in Synthesis of Macromolecules: A biochemical analysis of factors regulating gene expression in Blastocladiella emersonil. 4) Protein Modifying Reactions in Vitro: Studies of aminoacyl-tRNA-protein transferases, angiotensin-converting enzyme, and enzymes concerned with metabolism of thyroid hormones. 5) Control of Gene Expression and Metabolic Pathways: The analysis of changes in cellular carbohydrate metabolism following cell transfomation by avian sarcoma viruses. 6) Molecular Mechanims in Morphogenesis: Studies of the morphogenesis and differentiation of hydra.